Electromagnetic waves (such as radio-frequency (RF) waves, light waves, and waves in other portions of the electromagnetic spectrum) are used for a wide range of applications. For example, electromagnetic waves are used for communications, ranging and detection, wireless power transmission, and many other applications. For RF transmissions, a signal including one or more electromagnetic waveforms is generated by a transmitter and emitted from an antenna coupled to the transmitter. For light transmissions, the signal is generated by a source, such as a laser, that generates a beam of light and optics, such as lenses, reflectors, etc., are used to direct the beam of light in a particular direction. Whether the signal is RF-based or light-based, a receiving device typically converts the signal from a propagating electromagnetic wave into an electrical signal (e.g., an alternating current (AC) or direct current (DC) in a conductor) for use. To make use of the signal, the receiving device (or a portion thereof) must intersect the electromagnetic wave in a manner that allows the receiving device to convert enough of the energy of the electromagnetic wave into the electrical signal.
Many receiving devices are directional (e.g., they have higher gain in some directions than in others). Thus, how much of the energy transmitted by the transmitting device is converted into the electrical signal at the receiving device can depend, in part, on the relative positions of the signal transmitter and the receiving device.